Performance data is defined by Nagios as “everything after the | of the plugin output” - please refer to Nagios documentation for information on capturing this data to logfiles. However, it is the responsibility of the plugin writer to ensure the performance data is in a “Nagios plugins” format. This is the expected format:

'label'=value[UOM];[warn];[crit];[min];[max]

Notes:

space separated list of label/value pairs

label can contain any characters

the single quotes for the label are optional. Required if spaces, = or ' are in the label

label length is arbitrary, but ideally the first 19 characters are unique (due to a limitation in RRD). Be aware of a limitation in the amount of data that NRPE returns to Nagios

to specify a quote character, use two single quotes

warn, crit, min/ or max/ may be null (for example, if the threshold is not defined or min and max do not apply). Trailing unfilled semicolons can be dropped

min and max are not required if UOM=%

value, min and max in class [-0-9.]. Must all be the same UOM

warn and crit are in the range format (see Section 2.5). Must be the same UOM